virtualbox.org

Shared Folder permissions control doesn't work in Virtual Box, at least not with a Windows host on any current or recent version. This can be seen by simply using your VM to select a file on the host, change its permission to read-only, and notice that it has no effect. I want to use source control software between the VM and its host but that's impossible if permission control doesn't work. I'm not talking about fancy user rights management; I'm just talking about the read-only flag.

Is there a way to make it work or is there a bug fix to happen some day?

It seems that this is indeed a bug. Somehow, the file properties aren't loaded properly. Please report this as a bug. See the VirtualBox FAQ for a link to the TRAC bug system. You need a separate account though.

As a work around, you can use normal network shares.